Abstract
A Carnot-cycle magnetic refrigerator has been designed, built, and tested in the temperature range of ~4 K to ~15 K. Gadolinium gallium garnet in the rim of a wheel is the refrigerant. The wheel rim rotates through a gap between two superconducting Helmholtz coils that produce a magnetic field of up to 6 T. Helium gas is used as the heat-transfer fluid in the hot and cold regions of the wheel. The refrigerator performance has been measured in an open-cycle flow system because no suitable low-temperature helium gas pumps were available for closed loop circulation of helium gas. Over one watt of cooling power with a temperature span of several degrees was achieved. At low frequencies the cooling power and temperature changes of the refrigerator match the entropy-temperature data used in the design. Problems associated with friction and gas mixing limit the performance at frequencies above about 0.1 Hz. Separate friction measurements suggest that gas flow control is the dominant problem that needs to be solved before significant improvement in refrigerator operation can be expected. The present measured efficiency is about 20% of Carnot if the drive motor efficiency is ignored. With friction and other losses in the drive motor mechanism, the overall efficiency is ~1% of Carnot.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
See, for example, the proceedings of any Applied Superconductivity or Cryogenic Engineering Conference, such as “Advances in Cryogenic Engineering”, Vol. 29, Plenum, New York (1984) p. 29ff.
CTI, Air Products, CVI, Cryomech, Cryosysterns, and others make small gas refrigerators reaching ~4 K with a J-T loop
J. A. Barclay, Magnetic refrigeration for low-temperature applications; in: “Proc. of Third Cryocooler Conference”, N.B.S. SP 698, Boulder, Colorado, (1984) p. 20–32.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1986 Plenum Press, New York
About this chapter
Cite this chapter
Barclay, J.A., Stewart, W.F., Overton, W.C., Candler, R.J., Harkleroad, O.D. (1986). Experimental Results on a Low-Temperature Magnetic Refrigerator. In: Fast, R.W. (eds) Advances in Cryogenic Engineering. Advances in Cryogenic Engineering, vol 31. Springer, Boston, MA. https://doi.org/10.1007/978-1-4613-2213-9_84
Download citation
DOI: https://doi.org/10.1007/978-1-4613-2213-9_84
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4612-9299-9
Online ISBN: 978-1-4613-2213-9
eBook Packages: Springer Book Archive